I don't use to fave DD's, but it's Garnet, and in a cool style that remember me a traditional watercolor artworks, and reminded me Shoujo Kakumei Utena, a manga that was an inspiration for Steven Universe.
This is really beautiful piece and an interesting combination of stylistically completely different worlds. Turns out they work really well. I love the dress and her pose. There's very nice Mucha resemblance starting from the flow of lines. The Mucha's/Art Nouveau ornamental frames seem often a bit complicated and difficult to make work with the character in image, but in your work they are in a very good balance so that neither stands out in a wrong way. The colour palette is very pleasing. Knowing Garnet's colours I often see art of her with only those exact colours, which can make the image somewhat suffocating. The little amount of green and yellow make the palette nicely fresh. Congrats for the DD, well deserved!